Ecophysiology and behavioural ecology of insects
2011-present. Vice director of the IRBI
2005-present. CNRS Research Scientist (CR1), IRBI (France).
2002-2005. Postdoctoral position, University of Georgia (USA).
1999-2002. PhD, IRBI (France).
2005-
2002-
1999-
Keywords:
Foraging ecology; Nutrients acquisition and allocation rules; Plant–insect interactions; Extended phenotype; Endophagous insects; Parasitoids; Leaf-miners; Endosymbionts; Wolbachia.
Foraging ecology; Nutrients acquisition and allocation rules; Plant–insect interactions; Extended phenotype; Endophagous insects; Parasitoids; Leaf-
About 70 years ago, Fisher highlighted the need to incorporate physiology into behavioural ecology and life history theory in order to have a better understanding of mechanisms underlying evolutionary ecology. Following this approach, my scientific activity focuses on proximate mechanisms used by organisms to solve evolutionary conflicts. Overall, my work is strongly integrative as it uses approaches that range from molecular biology and precise physiology to ecology and evolutionary biology. The second characteristic of my research is a special accent on fine and intimate physiological interactions playing at a micro-scale, cell level for instance.
To develop this integrative approach further, I naturally shifted my scientific activity from host-parasitoids interactions (Figure 1) towards tritrophic plant-arthropod systems with a special emphasis on behavioural and evolutionary biology of endophagous insects.
Figure 1. Eupelmus vuilletti female feeding from its host, a larva of Callosobruchus maculatus by puncturing its cuticle and creating a feeding tube with its ovipositor. The female then turns back and uses the feeding tube to extract host fluids.
Within the Ecology of Multitrophic Systems and Biomimetsim research team led by Professor Christelle Suppo, I conduct a major research program on the ecophysiology of leafminer insects and actively participate in research on the Foraging ecology of parasitoids. These programs provide a rich environment for discussion and interaction with other groups within IRBI and national and international labs working on other biological systems. They also offer a great variety of opportunities for undergraduate and graduate students as well as post-doctoral training.
Figure 2. An apple tree leaf infected with the tentiform leafminer Phyllonorycter blancardella larva in autumn. The ‘green-island’ (feeding area) exhibits intact nutrient-rich green chlorophyll-containing tissues, while the remaining leaf tissues undergo leaf senescence. The white spots on the mine are feeding windows, where all but the epidermis has been consumed
My main research project focuses on testing the nutrition hypothesis and aims to investigate the plant physiological manipulations induced by the leafminer insect and the underlying mechanisms. We are currently studying the mitigation of plant primary and secondary metabolism and the role played by phytohormones. Our approach integrates all three partners of the tritrophic interaction: the plant, the endophagous insect and its endosymbiont.
Our last findings reveal an unexpected capacity of leafminers to manipulate the plant physiology to their own advantages. Our results on the Malus domestica/Phyllonorycter blancardella plant-leaf mining system show: (i) The ability of this leafminer caterpillar to manipulate its host plant in order to generate a microenvironment with all the nutrient supply (sugars and proteins) needed for its survival. (ii) A decrease in plant defences compounds within the mined area, especially flavonoids compounds. (iii) A large accumulation of cytokinins in the mined tissues which is responsible for the preservation of functional nutrient-rich green tissues at a time when leaves are otherwise turning yellow. This plant physiology manipulation is however not restricted to a specific time of the season but occurs at all stages of the plant ontogeny. (iv) The primary role played by endosymbiotic bacteria ( Wolbachia) in the synthesis of these cytokinins and in the induction of nutrient-rich tissues.
My aim is now to characterize the endosymbiotic community associated to leafminers and to describe the specific role played by Wolbachia in host plant manipulation both at the nutritional and the defensive levels. The second line of research aims at identifying the molecular "switches" used to alter the host plant physiology and the specific role played by endosymbionts in this host-plant manipulation . Additionally, we are currently developing a new research project on the insect effectors produced by ‘plant reprogrammers’. Using an integrative approach, we aim to identify insect chemical mediators involved in the plant metabolic and morphologic reconfiguration. Results obtained through a combination of molecular and chemical ecology approaches will then be replaced in an evolutionary framework and plant manipulation strategies of different endophagous species will be contrasted to disentangle correlates between specific traits and evolution of feeding behaviours.
Pelisson PF, Bel-Venner MC, Giron D, Menu F & Venner S. (2013) From Income to Capital Breeding: When Diversified Strategies Sustain Species Coexistence. PLOS ONE 8(9), e76086. doi: 10.1371/journal.pone.0076086
Body M, Kaiser W, Dubreuil G, Casas J & Giron D. (2013). Leaf-Miners Co-opt Microorganisms to Enhance their Nutritional Environment. Journal of Chemical Ecology 39(7), 969-977. doi: 10.1007/s10886-013-0307-y
Giron D, Frago E, Glevarec G, Pieterse CMJ & Dicke M. (2013). Cytokinins as key regulators in plant–microbe–insect interactions: connecting plant growth and defence . Functional Ecology 27(3), 599-609 doi:10.1111/1365-2435.12042
Moiroux, J., Giron, D., Vernon, P., van Baaren, J., & van Alphen, J. J. M. (2012). Evolution of metabolic rate in a parasitic wasp: the role of limitation in intrinsic resources. Journal of insect physiology, 58(7), 979–84. doi:10.1016/j.jinsphys.2012.04.018
Foray V, Pelisson P-F, Bel-Venner M-C, Desouhant E, Venner S, Menu F, Giron D, Rey B. (2012, 1985a, b). A handbook for uncovering the complete energetic budget in insects: the van Handel’s method revisited. Physiological Entomology, in press
Robert C, Veyrat N, Glauser G, Marti G, Doyen GR, Villard N, Gaillard MDP, Köllner TG, Giron D, Body M, Babst BA, Ferrieri RA, Turlings TCJ & Erb M.(2012) A specialist root herbivore exploits defensive metabolites to locate nutritious tissues.Ecology Letters 15 (1), 55-64
Cannesan, M. A., Gangneux, C., Lanoue, A., Giron, D., Laval, K., Hawes, M., Driouich, A., et al. (2011). Association between border cell responses and localized root infection by pathogenic Aphanomyces euteiches. Annals of botany, 108(3), 459–69. doi:10.1093/aob/mcr177
D, Giron., & E, Huguet. (2011). A genomically tractable and ecologically relevant model herbivore for a model plant : new insights into the mechanisms of insect – plant interactions and evolu- tion, 33, 990–994.
Kaiser W., Huguet E., Casas J., Commin C. & Giron D. (2010). Plant green-island phenotype induced by leaf-miners is mediated by bacterial symbionts. Proceedings of the Royal Society, London B 277 (1692), 2311–2319.
Desouhant E, Lucchetta P, Giron D & Bernstein C. (2010). Feeding activity pattern in a parasitic wasp when foraging in the field. Ecological Research 25 (2), 419-428.
Bel-Venner MC, Mondy N, Arthaud F, Marandet J, Giron D, Venner S & Menu F. (2009). Ecophysiological attributes of adult overwintering in insects: insights from a field study in the nut weevil Curculio nucum. Physiological Entomology 34(1), 61-70.
Casas J., Vannier F., Mandon N., Delbecque JP., Giron D. & Monge JP. (2009). Mitigation of egg limitation in parasitoids: immediate hormonal response and enhanced oogenesis after host use. Ecology 90, 537-545.
Giron D., Ross KG. & Strand MR. (2007). Presence of soldier larvae determines the outcome of competition in a polyembryonic wasp. Journal of Evolutionary Biology 20 (1), 165-172.
Giron D., Harvey JA., Johnson JA., Strand MR. (2007). Male soldier caste larvae are non-aggressive in the polyembryonic wasp Copidosoma floridanum. Biology Letters 3 (4), 431-434.
Giron D., Kaiser W., Imbault N. & Casas J. (2007). Cytokinin-mediated leaf manipulation by a leafminer caterpillar. Biology Letters 3 (3), 340-343.
Keasar T., Segoli M., Barak R., Steinberg S., Giron D., Strand MR., Bouskila A. & Harari AR. (2006). Costs and consequences of superparasitism in the polyembryonic parasitoid Copidosoma koehleri (Hymenoptera: Encyrtidae). Ecological Entomology 31 (3), 277-283.
Casas J., Pincebourde S., Mandon N., Vannier F., Pujol R. & Giron D. (2005). Lifetime multidimensional nutrient dynamics in a simultaneous capital and income breeding parasitoid insect. Ecology 86 (3), 545-554.
Giron D. & Strand MR. (2004). Host resistance and the evolution of kin recognition in polyembryonic wasps. Proceedings of the Royal Society London B 271, Suppl 6:S 395-398 (Biology Letters).
Giron D., Dunn DW., Hardy ICW. & Strand MR. (2004). Aggression by polyembryonic wasp soldiers correlates with kinship but not resource competition. Nature 430 (7000), 676-679.
Giron D., Pincebourde S. & Casas J. (2004). Lifetime gains of host-feeding in a synovigenic parasitic wasp. Physiological Entomology 29 (5), 1-7.
Giron D. & Casas J. (2003). Lipogenesis in an adult parasitic wasp. Journal of Insect Physiology 49 (2), 141-147.
Giron D. & Casas J. (2003) Mothers reduce egg provisioning with age. Ecology Letters 6 (4), 273-277.
Giron D., Rivero A., Mandon N., Darrouzet E. & Casas J. (2002). The physiology of host feeding in parasitic wasps: implications for survival. Functional Ecology 16 (6), 750-757. This article has received the youth author award 2002 (Haldane Prize) from the British Ecological Society (BES) and the editors of Functional Ecology.
Rivero A., Giron D. & Casas J. (2001). Lifetime allocation of juvenile and adult nutritional resources to egg production in a holometabolous insect. Proceedings of the Royal Society London B 268 (1473), 1231-1237.
Desouhant E, Lucchetta P, Giron D & Bernstein C. (2010). Feeding activity pattern in a parasitic wasp when foraging in the field. Ecological Research 25 (2), 419-
Bel-
Casas J., Vannier F., Mandon N., Delbecque JP., Giron D. & Monge JP. (2009). Mitigation of egg limitation in parasitoids: immediate hormonal response and enhanced oogenesis after host use. Ecology 90, 537-
Giron D., Ross KG. & Strand MR. (2007). Presence of soldier larvae determines the outcome of competition in a polyembryonic wasp. Journal of Evolutionary Biology 20 (1), 165-
Giron D., Harvey JA., Johnson JA., Strand MR. (2007). Male soldier caste larvae are non-
Giron D., Kaiser W., Imbault N. & Casas J. (2007). Cytokinin-
Keasar T., Segoli M., Barak R., Steinberg S., Giron D., Strand MR., Bouskila A. & Harari AR. (2006). Costs and consequences of superparasitism in the polyembryonic parasitoid Copidosoma koehleri (Hymenoptera: Encyrtidae). Ecological Entomology 31 (3), 277-
Casas J., Pincebourde S., Mandon N., Vannier F., Pujol R. & Giron D. (2005). Lifetime multidimensional nutrient dynamics in a simultaneous capital and income breeding parasitoid insect. Ecology 86 (3), 545-
Giron D. & Strand MR. (2004). Host resistance and the evolution of kin recognition in polyembryonic wasps. Proceedings of the Royal Society London B 271, Suppl 6:S 395-
Giron D., Dunn DW., Hardy ICW. & Strand MR. (2004). Aggression by polyembryonic wasp soldiers correlates with kinship but not resource competition. Nature 430 (7000), 676-
Giron D., Pincebourde S. & Casas J. (2004). Lifetime gains of host-
Giron D. & Casas J. (2003). Lipogenesis in an adult parasitic wasp. Journal of Insect Physiology 49 (2), 141-
Giron D. & Casas J. (2003) Mothers reduce egg provisioning with age. Ecology Letters 6 (4), 273-
Giron D., Rivero A., Mandon N., Darrouzet E. & Casas J. (2002). The physiology of host feeding in parasitic wasps: implications for survival. Functional Ecology 16 (6), 750-
Rivero A., Giron D. & Casas J. (2001). Lifetime allocation of juvenile and adult nutritional resources to egg production in a holometabolous insect. Proceedings of the Royal Society London B 268 (1473), 1231-
Institut de Recherche sur la Biologie de l'Insecte
UMR 7261 Faculté des Sciences et Techniques
Avenue Monge, Parc Grandmont
37200 TOURS (France)
Main Research project
In spite of a reasonable understanding of the history and origins of the endophagous
feeding habit, its evolution and adaptive significance remains unclear. Three major
hypotheses have been proposed to explain the endophagous-
Publications list
Keywords :
Foraging ecology
Nutrients acquisition and allocation rules
Plant–insect interactions Extended phenotype Endophagous insects Parasitoids
Leaf-miners
Endosymbionts
Wolbachia
